Retractable Traction System

ABSTRACT

A system is provided for retractably deploying traction of a wheel. The system includes a set of grippers, each gripper having a cleat and a radially disposed strut. The system further includes a set of first poles, each first pole coupled to one of the struts, the first pole configured to support motion of its corresponding strut between a parked position and an engaged position, wherein, in the engaged position, the corresponding cleat is axially disposed and engaged against the tread of the wheel and, in the parked position, the corresponding cleat is disengaged from the tread of the wheel. The system includes a first faceplate configured to rotate with the wheel. The system further includes a cleat deployment mechanism having a second faceplate rotatably coupled to the first faceplate, and a set of second poles, each second pole coupled to one of the struts and to the second faceplate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. application Ser. No.16/248,151, filed Jan. 15, 2019, now U.S. Pat. No. 11,155,131, whichclaims priority from U.S. Provisional Application No. 62/617,350, filedJan. 15, 2018, the disclosure of each of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present invention relates to traction systems, and more particularlyto retractable traction systems for vehicles and machines having one ormore wheels.

BACKGROUND ART

One major challenge facing standard wheels of vehicles is the loss oftraction in icy or snowy environments. This is particularly true in coldclimates, where vehicles having tires with increased traction are soughtout for safety. Among the conventional solutions are snow tires and tirechains, which require the user of the vehicle or other machinery toinstall and uninstall the snow tires or tire chains. For example, theuser has to plan ahead of a snowstorm or snow season to install the snowtires or tire chains. Further, those without the necessary tools orskills to install these conventional solutions are disadvantaged becausethey must either do without enhanced traction (and risk their safety onthe road) or pay for the installation. In another example, robots thatare deployed to snowy climates, or even other planets, do not typicallyhave humans to install these conventional solutions to increase thetraction of the robot's tires.

SUMMARY OF THE EMBODIMENTS

In accordance with one embodiment of the invention, a system is providedfor retractably deploying enhanced traction of a wheel having a treadand an axis of rotation. The system includes a set of grippers, eachgripper having a cleat and a radially disposed strut. The system furtherincludes a set of strut mounts, each strut mount coupled to one of thestruts, the strut mount configured to support motion of itscorresponding strut between a parked position and an engaged position,wherein, in the engaged position of such strut, the corresponding cleatis axially disposed and engaged against the tread of the wheel and, inthe parked position of such strut, the corresponding cleat is disengagedfrom the tread of the wheel, and a faceplate configured to rotate withthe wheel, wherein when such strut is in the engaged position, suchstrut is coupled to the faceplate and moves with the faceplate and thewheel, and when such strut is in the parked position the strut causesthe cleat to be withdrawn in a radial direction from the tread. Thesystem further includes a cleat deployment mechanism, coupled to thestruts, configured on actuation to cause automatic deployment of thestruts into the engaged position.

In a related embodiment, the cleat deployment mechanism includes acircular raceway defining a center that coincides with the axis ofrotation and a set of sliders mounted for rotational motion in theraceway. The system further includes a second set of sliders mounted forrotational motion in a second raceway concentric with the raceway, and asecond set of strut mounts, each second strut mount coupled to one ofthe second sliders and to one of the struts. Optionally, each strut iscoupled to one of the sliders and to one of the second sliders.

In another related embodiment, the system further includes a set ofpushers protruding from the faceplate, wherein as the faceplate rotateswith the wheel, each of the set of pushers is configured to couple witha corresponding strut. Optionally, the system includes a set of pegs,each peg moveably coupled to a corresponding one of the set of strutmounts, each peg having a parked and engaged position, wherein each pegis configured to move from its parked position to its engaged positionso that each peg comes into contact with a corresponding one of the setof pushers.

In yet another related embodiment, the system further includes a set ofsprings, each spring mounted to an arm of one of the set of strutmounts, each spring configured to decompress to cause a correspondingone of the set of pegs to move to its engaged position. Optionally, thesystem includes a stopper configured to block a path of a first one ofthe set of sliders in the raceway during the parked position of thestrut, wherein the stopper is further configured to compress the springof the corresponding arm of a first one of the strut mounts and push thepeg of the corresponding first one of the strut mounts into its parkedposition. Optionally, the stopper is configured to move from the pathbefore the strut is in the engaged position.

In yet another related embodiment, the system further includes acontroller coupled to the stopper, the controller configured to causemovement of the stopper. Optionally, the controller is configured toreceive an activation signal from a vehicle computer system or remotedevice, the activation signal causing the controller to move the stopperout of the path. Optionally or alternatively, the controller isconfigured to receive a deactivation signal from a vehicle computersystem or remote device, the deactivation signal causing the controllerto move the stopper into the path. Optionally, the remote device is aremote starter for a vehicle or a network-enabled device. Optionally,the network-enabled device is a smartphone, tablet, or computer. In arelated embodiment, the system further includes a cable coupled directlyor indirectly to the stopper, wherein the cable is configured to causemovement of the stopper.

In another related embodiment, the system further includes a secondstopper configured to block reverse movement of a last one of the set ofsliders in the raceway. In yet another related embodiment, the systemfurther includes a set of cups having at least one cup wall, the cupmovably coupled to a pivot mount of a corresponding one of the strutmounts, the cup having a parked and engaged position, wherein each cupis configured to be adjusted from its parked position to its engagedposition so that the at least one cup wall comes into contact with acorresponding one of the set of pushers. Optionally, the pivot mountconfigured to be adjusted by at least one electromechanical solenoidhaving a plunger configured to engage with a subject end of the pivotmount to cause a corresponding one of the set of cups to move to itsengaged position. Optionally, pivot mount configured to be adjusted byat least one torsion spring configured to engage with a subject end ofthe pivot mount to cause a corresponding one of the set of cups to moveto its engaged position. Optionally, the cleat is rotatably mounted tothe strut.

In a related embodiment, the cleat deployment mechanism includes asecond faceplate rotatably connected to the faceplate, such that thestruts are in the parked position when the second faceplate is in afirst position relative to the faceplate and the struts are in theengaged position when the second faceplate is in a second positionrelative to the faceplate, the first position being different than thesecond position. The cleat deployment mechanism may further include aspring that moves the second faceplate from the first position to thesecond position. The cleat deployment mechanism may further include amechatronics cylinder that moves the second faceplate from the secondposition to the first position.

In accordance with another embodiment of the invention, a vehicle wheelincludes a traction system according to any of the embodiments describedherein, wherein a faceplate of the traction system is configured to becoupled to a side of the wheel, the side of the wheel facing toward avehicle chassis. Optionally, the faceplate is mounted to the side of arim of the wheel. Optionally, the faceplate is a part of a rim of thewheel.

In accordance with another embodiment of the invention, a vehicle wheelincludes a traction system according to any one of the embodimentsdescribed herein, wherein a faceplate of the traction system isconfigured to be mounted to a side of a rim of the wheel, the side ofthe rim facing toward a vehicle chassis.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of embodiments will be more readily understood byreference to the following detailed description, taken with reference tothe accompanying drawings, in which:

FIGS. 1A-1B are perspective views of an exemplary embodiment of aretractable traction system configured to operate with a wheel, inaccordance with an embodiment of the invention;

FIG. 2A is a perspective view of a first subassembly of an exemplaryretractable traction system, in accordance with another embodiment ofthe invention;

FIG. 2B is a perspective view of a subset of components of theretractable traction system shown in FIG. 2A, in accordance with anotherembodiment of the invention;

FIG. 3 is a perspective view of a conventional wheel coupled to a secondsubassembly of the retractable traction system, in accordance withanother embodiment of the invention;

FIGS. 4A-4E are front views of an exemplary retractable traction system,wherein each figure illustrates a portion of the process of deployingand/or retracting the retractable traction system, in accordance withanother embodiment of the invention;

FIGS. 5A-5B are diagrams of exemplary control systems for use with oneor more retractable traction systems, in accordance with anotherembodiment of the invention;

FIG. 6A is a flowchart of an exemplary activation process of theretractable traction system, in accordance with another embodiment ofthe invention;

FIG. 6B is a flowchart of an exemplary deactivation process of theretractable traction system, in accordance with another embodiment ofthe invention;

FIGS. 7A-7C are diagrams illustrating an exemplary solenoid mechanismthat can be applied to a catch system of an exemplary retractabletraction system, in accordance with another embodiment of the invention;

FIG. 8A is a diagram of an exemplary catch system for the exemplaryretractable traction system, in accordance with another embodiment ofthe invention; FIG. 8B is a diagram of the exemplary catch system whenthe retractable traction system is activated, in accordance with anotherembodiment of the invention; FIG. 8C is a diagram of the exemplary catchsystem when the retractable traction system is deactivated, inaccordance with another embodiment of the invention;

FIGS. 9A-9B is a diagram combining the exemplary catch system of FIGS.8A-8C with the solenoid mechanism illustrated in FIGS. 7A-7C, inaccordance with another embodiment of the invention;

FIG. 10 is a diagram of the catch system illustrated in FIGS. 9A-9Bincorporated into the exemplary retractable traction system, inaccordance with another embodiment of the invention;

FIG. 11 is a partial view of an exemplary retractable traction systemusing torsion springs in accordance with another embodiment of theinvention;

FIGS. 12A and 12B are a perspective view and side view, respectively, ofan embodiment of a retractable traction system mounted on a wheel, andFIG. 12C is a perspective view of a subset of components of theretractable traction system shown in FIGS. 12A-12B, in accordance withanother embodiment of the invention;

FIGS. 13A and 13B are a perspective view and side view, respectively, ofanother embodiment of a retractable traction system mounted on a wheelin accordance with another embodiment of the invention;

FIGS. 14A and 14B are a front view and side view, respectively, ofanother retractable traction system mounted on a wheel in a parked ordisengaged position, and FIG. 14C is an exploded perspective view of theretractable traction system shown in FIGS. 14A-14B in accordance withanother embodiment of the invention; and

FIG. 15A is a front view, FIG. 15B is a side view, and FIG. 15C is aperspective front view of the retractable traction system shown in FIGS.14A-14B in an engaged position in accordance with an embodiment of theinvention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Definitions. As used in this description and the accompanying claims,the following terms shall have the meanings indicated, unless thecontext otherwise requires:

A “set” includes at least one member.

A “wheel” is an assembly that is removably attachable to an axle of avehicle or machine and includes a traction element, such as a tire,having a tread that is in contact with the ground when the vehicle ormachine is in use. (Note that this definition is broader than sometechnical usages of the term “wheel,” which may exclude the tire.)

Retractable Traction System

FIGS. 1A-1B are perspective views of an exemplary embodiment of aretractable traction system 104 configured to operate with a wheel 102.The wheel 102 can be a conventional wheel of, for example, anautomobile. In some embodiments, the retractable traction system 104 canbe configured to operate with other wheel types, such as non-standardwheels or wheels for robots, machinery, military equipment, spaceequipment, etc. In FIGS. 1A-1B, a conventional wheel 102 is illustratedand includes tire 106. The retractable traction system 104 can bedescribed in two major portions, a first subassembly 200 (described infurther detail in FIG. 2) that is positioned about an axle 108 on whichthe wheel 102 is mounted and a second subassembly 300 (described infurther detail in FIG. 3) that is mounted to a face of the wheel 102 andis configured to engage with the first subassembly 200.

FIG. 2A is a perspective view of the first subassembly 200 of anexemplary retractable traction system 104. The first subassembly 200includes a set of grippers 203 a-203 d (collectively referred to as 203)that include a cleat 202 a-202 d (collectively referred to as 202)removably mounted to a corresponding strut 204 a-204 d (collectivelyreferred to as 204) to provide increased traction for the wheel. In thisembodiment, each of cleats 202 is coupled to a corresponding one ofstruts 204. Though there are four grippers 203 shown in the firstsubassembly 200, there can be as few as three grippers to provideeffective enhanced traction. In some embodiments, the number of gripperscan be determined by the size and configuration of the wheel. Forexample, a large sized wheel may require eight grippers. For militarytanks that utilize a band coupled to multiple wheels, there may be ahigher number of grippers to accommodate the size and shape of thesurface that requires enhanced traction. The grippers may be any shapeand have any surface configuration suited to increase traction for awheel. For example, FIGS. 12A-12C show a surface configuration havingspikes (1222 a, 1222 b, 1222 c, 1222 d) and FIGS. 13A-13B show a surfaceconfiguration having chain links (1322 a, 1322 b, 1322 c, 1322 d).

In some embodiments, each strut 204 is coupled to a slider that isconfigured to guide the strut 204 around the wheel during the deploymentof the retractable traction system 104. The exemplary cleats 202 a-202 dare mounted to struts 204 a-204 d, respectively, which are each coupledto at least one slider 206 a-206 d (collectively referred to as 206),208 a-208 d (collectively referred to as 208). The first subassembly 200shown in FIGS. 2A-2B include both a set of outer sliders 206 and innersliders 208. In some embodiments, the struts 204 may be coupled only toinner sliders 208.

The first subassembly 200 includes an inner set of sliders {inner slider1, inner slider 2, . . . inner slider M}, where M is a whole number, andan outer set of sliders {inner slider 1, inner slider 2, . . . innerslider N}, where N is a whole number. In the preferred embodimentdescribed herein, M=N, but in other embodiments, M can be different thanN. In this case, where M=N, an inner slider 208 a-208 d and an outerslider 206 a-206 d are paired with one another. Thus, as shown in FIGS.2A-2B, inner slider 208 a is paired with outer slider 206 a, innerslider 208 b is paired with outer slider 206 b, and so on. Each slider206 a-206 d, 208 a-208 d is coupled to a respective strut mount 207a-207 d (collectively referred to as 207), 209 a-209 d (collectivelyreferred to as 209) that is configured to anchor the strut 204 such thatthe strut 204 can move relative to the respective slider 206, 208.

FIG. 2B is a perspective view of a subset of components of the firstsubassembly 200 shown in FIG. 2A. As more clearly shown in FIG. 2B, eachexemplary strut 204 is coupled to one inner slider 208 a-208 d and oneouter slider 206 a-206 d. For example, strut 204 a is coupled to anouter slider 206 a via strut mount 207 a such that the strut 204 a isable to move relative to the slider 206 a with two degrees of freedom214 a and 214 b. Specifically, strut 204 a can rotate about pivot pin216 (of the strut mount 207 a) with rotation 214 a and slide relative topivot pin 216 with translation 214 b. In this embodiment, the strut 204a is also coupled to an inner slider 208 a via pivot pin 218; the strut204 a can rotate around pivot pin 218 with rotation 220. The sum effectof these mechanisms is that each gripper can be individually guidedaround the wheel 102 by interaction with the outer and inner sliders 206and 208, respectively. Note on each strut mount 207 (of both inner andouter sliders 208, 206) are two sets of pegs 222 (shown as 222 a-222 d),a forward peg (for example, peg 222 a or 222 b) and reverse peg (forexample, peg 222 c or 222 d), that are used to catch the pushers of thesecond subassembly 300 (described further below for FIG. 3).

Returning to FIG. 2A, the first subassembly 200 includes an outerraceway 210 and an inner raceway 212 that each holds a set of sliders206, 208. The outer raceway 210 holds the set of outer sliders 206 a-206d and the inner raceway 212 holds the set of inner sliders 208 a-208 d.In some embodiments, the sliders 206, 208 may be shaped to have a flangeso as to slidably fit into the slots formed into walls of the raceways.The radius of the curvature of the slider shape corresponds to theradius of the respective raceway 210, 212.

In this embodiment, the first subassembly 200 has fourgripper-assemblies 224 (shown as 224 a-224 d in FIGS. 4A-4E below), eachof which include gripper 203 (composed of a cleat 202 and a strut 204),an outer slider 206, an outer strut mount 207, an inner slider 208, andan inner strut mount 209. These gripper-assemblies 224 are configured tobe held in place by at least a first stopper 226 a. Note that this firststopper 226 a is positioned to stop the gripper-assemblies 224 frommoving in the direction 228 of deployment when the first subassembly 200is in the “parked” position. In some embodiments, the first stopper 226a has an outer protrusion 228 a configured to stop or hold in place atleast outer slider 206 a and an inner protrusion 228 b configured tostop or hold in place at least inner slider 208 a. In this embodiment,the gripper-assemblies 224 are held on each end by the first stopper 226a and the second stopper 226 b (collectively referred to as stopper(s)226). In some embodiments, instead of a mechanical stopper 226 asprovided here, magnetic material can be used to keep the sliders 206,208 in place in its raceway 210, 212 until activated. Some embodimentsof the tractions system may make use of both mechanical stoppers andmagnetic material to keep sliders 206, 208 in place. Note that theexemplary strut mounts 207, 209 are shaped to interact with the one ormore stoppers 226 and each other. For example, the arms of the strutmounts 207 a, 209 a extend to push the peg 222 of its neighbor strutmount 207 b, 209 b to engage a pusher of the faceplate of the secondsubassembly 300. One or more stoppers 226 may be any shape allowing themto stop a slider (206 and/or 208) of the retractable traction system104. For example, one or more of the stoppers 226 may be flat such thatthere are no protrusions.

FIG. 3 is a perspective view of a conventional tire 106 of wheel 102coupled to the second subassembly 300 of the retractable traction system104. The second subassembly 300 includes a faceplate 301 in which a setof outer pushers 302 and a set of inner pushers 304 (shown as 304 a-304d) are mounted. In this embodiment, there is one outer pusher 302 andfour inner pushers 304 a-304 d (collectively referred to as 304). Theouter pusher(s) 302 are located at radial positions corresponding to thepositions of the pegs 222 of the outer sliders 206 in the firstsubassembly 200. The outer pusher 302 is configured to right the strutsduring retraction of the retractable traction system 104 to avoidcontact between the cleats and the tire surface, as described in moredetail below. The inner pusher(s) 304 are located at radial positionscorresponding to the positions of the pegs 222 of the inner sliders 208of the first subassembly 200. Thus, for example, the inner pusher 304 isconfigured to come in contact with peg 222 b and push it in an axialmotion so that the gripper-assembly 224 moves around the tire 106 ofwheel 102, as described more fully below.

In an exemplary embodiment, the faceplate 301 of the second subassembly300 can be coupled to the side of the wheel such that it is mounted tothe rim of the wheel (for instance, the inner rim facing the chassis ofthe vehicle). In another exemplary embodiment, the faceplate can be partof the rim of the wheel. In other words, the faceplate 301 can bemanufactured as part of the rim of the wheel.

Note that, while specific shapes are provided here for each of thecomponents of the exemplary embodiments of the retractable tractionsystem 104, a person skilled in the art would understand that othershapes, formed by various means, can achieve similar functionality andresults. For example, wheel 102 of the retractable traction system 104may be printed on three-dimensional (“3D”) printers without rims in amanner such that faceplate 301 is a part of wheel 102 itself.

Traction System Deployment

FIGS. 4A-4E are front views of an exemplary retractable traction system104, wherein each figure illustrates a portion of the process ofdeploying and/or retracting the retractable traction system 104. In eachof FIGS. 4A-4E, the second subassembly 300 is shown as a transparentcomponent so that the components of the first subassembly 200 arevisible. In FIG. 4E, the tire 106 is shown as a transparent componentfor context and is not shown in FIGS. 4A-4D in order to simplify thefigures. An example of the faceplate 301 is more clearly illustrated inFIG. 3. Note that any one or more of the processes described herein canbe actuated mechanically or electronically, whether automatically or bya user of the retractable traction system 104. Discussion of the controlof the retractable traction system 104 follows below.

FIG. 4A illustrates a “parked” position of the retractable tractionsystem 104, in which the set of gripper-assemblies 224 a-224 d (of firstsubassembly 200) are grouped near the top of the wheel (not shown). Insome embodiments, the gripper-assemblies 224 a-224 d can be heldtogether or in subsets along any side of the wheel, so long as theholding mechanism does not interfere with the normal operation of avehicle's wheel while the retractable traction system 104 is retracted(for example, not in use during normal road conditions). Note that, inthis “parked” or retracted mode, second subassembly 300 having pushers302, 304 continues to revolve about the axle as the wheel 102 turns (forexample, while driving in normal conditions). Specifically, none of thepushers 302, 304 catch the pegs 222 and instead go right past them asthe wheel 102 turns.

FIG. 4B illustrates the retractable traction system 104 duringdeployment in which the stoppers 226 a, 226 b are moved out of the wayof the inner and outer sliders 208, 206. The stopper 226 a moving awayfrom inner slider 208 a and outer slider 206 a causes the peg 222 b ofthe inner slider 208 a to move (with motion 401) from its parkedposition so that an inner pusher 304 of subassembly 300 will makecontact. This mechanism is facilitated by springs 402 that push the peg222 (e.g., peg 222 b) into position to be caught by the inner pusher 304(e.g., inner pusher 304 a). In some embodiments, the stoppers 226 a, 226b are controlled mechanically or electronically by a user orautomatically upon the initialization of the retractable traction system104. For example, the position of the stopper(s) 226 may be controlledby a cable accessible by a user, and the user may pull a cable in thevehicle to cause the stopper(s) 226 to move from the path of the one ormore sliders 208, 206.

FIG. 4C illustrates the retractable traction system 104 duringdeployment in which stoppers 226 a, 226 b are entirely out of the way ofthe inner and outer sliders 208, 206. Upon deployment of the retractabletraction system 104, inner pusher 304 a of second subassembly 300 makescontact with peg 222 b (also shown in the zoomed-in view 404). Thiscontact pushes inner slider 208 a along the inner raceway 212(counterclockwise, in this example). This causes the bottom of strut 204to move with the inner slider 208 a. Eventually, the gripper-assembly224 a is caused to move around the axis of rotation (in this case, theaxle 108 of the wheel).

FIG. 4D illustrates the retractable traction system 104 duringdeployment in which the gripper-assemblies 224a-224 d are pushed by therespective inner pushers 304 a-304 d, as detailed above forgripper-assembly 224 a. The inner pushers 304 are distributed inquadrants of the faceplate 301 of second subassembly 300 and thus causethe gripper-assemblies 224 to be approximately distributed around thetire 106 of wheel 102 (not shown). As shown in FIG. 4E, in someembodiments, as the gripper-assemblies 224 make their way around thetire 106 of wheel 102, the cleat 202 a may pivot at pin 406 relative tostrut 204 a (with rotation 408) so that contact between the ground 410and the cleat 202 a does not cause the cleat 202 a to break.

Retraction of the Retractable Traction System

The retraction of the exemplary retractable traction system 104 mirrorsmuch of the deployment process described above. In this embodiment, theretraction of the retractable traction system 104 can take place whilethe wheel 102 is in use (for example, switching to driving on plowedroads). In the retraction process, once the gripper-assemblies 224 aredeployed, as shown in FIG. 4E, stopper 226 a may be moved back into astopping position to enable the collection of gripper-assemblies 224into their “parked” mode. Specifically, stopper 226 a engages theforward peg 222 b of the inner slider 208 d such that the spring 402 iscompressed and peg 222 b moves in direction 412 (opposite to direction401). This causes the inner pusher 304 d to disengage from peg 222 b andmove past gripper-assembly 224 d. The stopping of a firstgripper-assembly 224 causes the remaining gripper-assemblies 224 to bestopped. The position of the pegs 222 b of each gripper-assembly 224 aresimilarly adjusted as each gripper-assembly 224 comes into contact withits neighboring gripper-assembly 224. This process can continue untilall of the gripper-assemblies 224 are removed from around the tire 106of wheel 102. In some embodiments, the outer pusher 302 rotates until itmakes contact with the peg 222 a and pushes it to group with othergripper-assemblies 224.

In yet another embodiment, portion 228 a of stopper 226 a engages theforward peg 222 a on the outer slider 208 d such that spring 402 iscompressed and peg 222 a moves in direction 412. This causes the outerpusher 302 to push the gripper-assemblies 224 into a vertical position(similar to that shown in FIG. 4A). As gripper-assemblies 224 come to avertical parked position, outer pusher 302 continues to move past eachnow-vertical gripper assembly 224 and, finally, move past the gripperassembly 224 d to attain the parked position of gripper-assemblies 224.In some embodiments, the outer pusher 302 may require at least onerotation of the wheel to push the gripper-assemblies 224 into thevertical parked position. Because the retractable traction system 104can be retracted or deactivated at any time, the outer pusher may be invarious positions relative to the gripper-assemblies 224 for any givendeactivation instance. Thus, for example, if the outer pusher 302 ispositioned behind the last gripper-assembly 224 to be parked, then onlyone rotation is necessary. Specifically, if the outer pusher 302 isbetween gripper-assemblies 224 b and 224 c (as shown in FIG. 4D) andstopper 226 a stops gripper-assembly 224 c, then the outer pusher 302can push gripper-assembly 224 b and effectively group allgripper-assemblies 224 a, 224 b, 224 c, and 224 d within one rotation ofthe wheel 102. However, in another example, if the outer pusher 302 isbetween gripper-assemblies 224 a and 224 b (as shown in FIG. 4D) andstopper 226 a stops gripper-assembly 224 c, outer pusher 302 can groupgripper-assemblies 224 a, 224 d, and 224 c within a first rotation ofthe wheel 102 and follow up to group gripper-assembly 224 b in thesecond rotation of the wheel 102. It can be understood by one skilled inthe art that the process described herein is applicable to the otherpossible positions of the outer pusher 302 for groupinggripper-assemblies 224 into their vertical parked position.

Control of Retractable Traction Systems

FIGS. 5A-5B are diagrams of exemplary control systems for use with oneor more retractable traction systems 104. FIG. 5A illustrates controlsystem 500 having a front controller 502 a coupled to the retractabletraction systems 104 of the front axle 504 a (one retractable tractionsystem 104 for each wheel) and a rear controller 502 b coupled to theretractable traction systems 104 of the rear axle 504 b (one retractabletraction system 104 for each wheel) of a vehicle. In some embodiments,the control signal originates from the vehicle computer system 506,which may have an automatic setting or a manual setting. In theautomatic setting, the vehicle may have a sensor configured to detect aparticular environmental condition, such as snow, ice, or mud, andautomatically send a control signal to each controller to deploy theretractable traction systems 104 of each wheel 102. In another example,a user may provide input to the vehicle computer system 506 (via a userinterface) to activate the retractable traction systems 104. In someembodiments, a remote device 508 can provide a control signal to eitherthe vehicle computer system 506 or directly to the controllers 502 a,502 b to deploy the respective retractable traction systems 104 based ondetected surface conditions ahead. For example, remote device 508 caninclude, e.g., a remote control device (such as a remote starter for avehicle), any network-enabled device (such as a smartphone, tablet, orlaptop computer), another vehicle ahead that detects the surfaceconditions, and/or a satellite capable of sending detected surfaceconditions. For example, the remote device 508 can have an app tocontrol the activation/deactivation of the retractable traction system104. If, for example, the retractable traction systems 104 are installedon a robot or autonomous vehicle, the remote device 508 can be thecontroller of the robot or autonomous vehicle. Note that in someembodiments, a vehicle may only have retractable traction systems 104 ona front or a rear axle 504 a, 504 b, instead of both. In such a case,only a single controller 510 may be used. In yet another example, asingle controller 510 can be coupled to and control all retractabletraction systems 104 on a vehicle. In some embodiments, the control ofthe stoppers and/or the retractable traction system 104 can becontrolled by a cable coupled directly or indirectly to the stopper(s),such that the cable causes movement of the stopper. For example, usercan activate the retractable traction system 104 by pulling on such acable from within the vehicle or exterior to the vehicle to activate ordeactivate the retractable traction system 104.

FIG. 5B illustrates a control system 512 in which each retractabletraction system 104 has its own controller. This is in contrast to theprevious example, where a single controller 510 could be coupled to twoor more retractable traction systems 104. Thus, controller 514 acontrols one retractable traction system 104, e.g., for one rear wheel516 a and controller 514 b controls another retractable traction system104, e.g., for the other rear wheel 516 b. In some embodiments,controllers 514 a and 514 b can work together to synchronize theirprocesses, such as the deployment and/or retraction of the retractabletraction systems 104.

FIG. 6A is a flowchart of an exemplary activation process 600 of theretractable traction system 104 described herein. In process 602, acontroller 510 or 514 a, 514 b of the retractable traction system 104receives an activation signal from, for example, the vehicle computersystem 506. In process 604, the first and second stoppers 226 arereleased or moved away from the gripper-assemblies 224. In process 606,the first inner pusher 304 a of the faceplate 301 of the secondsubassembly 300 engages with the first gripper-assembly 224, causing aslider of the first gripper-assembly 224 a to move in its raceway. Inprocess 608, the second pusher 304 b of the faceplate 301 of the secondsubassembly 300 engages with the second gripper-assembly 224 b, causinga slider of the second gripper-assembly 224 b to move in its raceway.This process occurs until the Nth slider is engaged and pushed to itsposition in the raceway (process 610).

FIG. 6B is a flowchart of an exemplary deactivation process 612 of theretractable traction system 104 described herein. In process 614, thestopper 226 a engages with a first slider and causes the slider todisengage from the first pusher 304 a of the faceplate 301. In process616, the first slider engages with the second slider and causes thesecond slider to disengage from the second pusher 304 b of the faceplate301. In process 618, the (N−1)th slider engages with the Nth slider andcauses the Nth slider to disengage from the Nth pusher of the faceplate.This process continues until each of the gripper-assemblies 224 isdecoupled from the wheel 102.

Other Embodiments

Other mechanisms may be used in place of the peg-pusher mechanism(“catch” system) described above. For example, in FIGS. 4A-4E, peg 222 bis moved between at least two positions to catch or avoid catching innerpusher 304 a. In another embodiment, one or more electromechanicalsolenoids can be incorporated into the first subassembly 200 to achievethe purpose of catching pushers of the second subassembly 300. In yetanother embodiment, torsion springs, or other types of springs, can beused in place of, or in addition to, the electromechanical solenoids tocause the catching of the pushers of the second subassembly 300.

FIGS. 7A-7C illustrate an exemplary solenoid mechanism that can beapplied to the catch system of the retractable traction system 104. FIG.7A shows pivot 702 coupled to first and second ball-shaped subjects 704a, 704 b (collectively referred to as 704). In this system, a firstelectromechanical solenoid 706 a has a plunger 708 a aimed at the firstsubject 704 a opposite a second electromechanical solenoid 706 b has aplunger 708 b aimed at the second subject 704 b (solenoids 706 a, 706 bare collectively referred as 706 and plungers 708 a, 708 b arecollectively referred to as 708).

FIG. 7B illustrates an activated state for the exemplaryelectromechanical solenoids 706. When the electromechanical solenoid 706is actuated by an electrical current, plunger 708 is caused to extendfrom the solenoid body 710 a, 710 b (collectively referred to as 710).For example, one or more controllers 502 a, 502 b, 510, 514 a, 514 b cansend a signal to activate the solenoid. This action causes the subjects704 to move in opposing directions about the pivot 702. In FIG. 7C, whenthe plungers 708 retract into the body 710, the subjects 704 remain inthe position to which they were pushed.

FIG. 8A is a diagram of an exemplary catch system for the retractabletraction system 104. The catch system 800 includes a pusher 802 and apivoting cup 804. The pivoting cup 804 is coupled to a two arms withsubjects 704 a, 704 b, used to pivot the cup according to the mechanismdescribed above for FIGS. 7A-7C and further described below for FIGS.9A-9B. The pivoting cup 804 has two cup walls 806 a, 806 b (collectivelyreferred to as 806). In some embodiments, the cup has one or more cupwalls 806. The configuration of the cup walls 806 a, 806 b allows thepusher 802 to pass through the pivoting cup 804 when the retractabletraction system 104 is deactivated. This is analogous to when the peg222 b is positioned away from the path of the pusher 304 a, asillustrated in FIGS. 4A-4E. Note that the pusher 802 is coupled to thefaceplate 301 of the second subassembly 300. For example, pusher 802 canbe positioned in a similar position to that of inner pusher 304 a.

FIG. 8B is a diagram of the exemplary catch system 800 when theretractable traction system 104 is activated. At this time, the pivotingcup 804 has been pivoted by opposing electromechanical solenoids 706. Bypivoting, the cup walls 806 a, 806 b have changed position such that atleast one cup wall 806 b blocks the path of the pusher 802. In someembodiments, the pusher has a “butterfly” shape so as to embrace theoutside of the cup wall 806 b during the pushing operation. FIG. 8C is adiagram of the exemplary catch system 800 when the retractable tractionsystem 104 is deactivated. FIG. 8C illustrates how the pivoting cup 804is adjusted to allow the pusher 802 get by the blocking cup wall 806 a.

FIGS. 9A-9B is a diagram combining the exemplary catch system 800 ofFIGS. 8A-8C with the solenoid mechanism illustrated in FIGS. 7A-7C. InFIG. 9A, the pivoting cup 804 is configured, in the deactivated state ofthe retractable traction system 104, to allow the pusher 802 to passbetween the two cup walls 806. In FIG. 9B, the pivoting cup 804 ispivoted by activated solenoids 706 a and 706 b (for example, via acontroller signal) to push subjects 708 a and 708 b, respectively,thereby blocking the path of the pusher 802. As the pusher 802 travelsvia the turning of the faceplate 301, it makes contact with a cup wall806 and pushes the cup 804.

FIG. 10 is a diagram of the catch system illustrated in FIGS. 9A-9Bincorporated into the retractable traction system 104. As provided inFIGS. 4A-4E, the retractable traction system 104 includes at least threegripper-assemblies 224. In this illustration, each of the inner sliders208 and outer slider 206 have a catch system 800 that is used to engagewith the pushers 802 a-802 d (collectively referred to as 802) when theretractable traction system 104 is activated. The exemplaryconfiguration provided in FIG. 10 otherwise operates similarly to thatprovided in FIGS. 4A-4E.

Although the above describes using one or more solenoids, otherelectromechanical systems may also be used. For example,electromechanical systems may include servomotors and/or stepper motorsthat may directly pivot cup 804 to engage and disengage pusher 802.

Exemplary Electronic Traction System

In an exemplary embodiment, one or more of sliders 206, 208 includeelectromagnets located in or behind each slider, wherein eachelectromagnet can be activated by an activation or control signal from acontroller coupled to the retractable traction system 104 (as discussedin more detail above). The electromagnets can be activated to hold thesliders in place by being magnetically attracted to a metalliccomponent, such as the walls of raceways 210, 212 (shown in FIG. 2A) ora metallic plate 109 (shown in FIG. 1B).

During the activation of the retractable traction system 104, thestopper 228 a moves away from the path of the sliders 206, 208. At thistime, the electromagnets are energized, holding the sliders 206, 208 inplace. A controller can send a control signal to de-energize theelectromagnet of a first inner slider 208 a. Once the first inner slider208 a is free to move along the raceway 212, the remaining sliders canmove by any of the mechanisms described in FIGS. 1-6 or FIGS. 7-10.

FIG. 11 is a partial view of an exemplary retractable traction system104. In this embodiment, torsion springs are used in place of theelectromechanical solenoids 706 a, 706 b to cause the catching of thepushers of the second subassembly 300. Thus, when the first inner slider208 a is freed to move along raceway 212, a torsion spring releases andpushes away from a neighboring slider 208 b. Cup 804 a pivots to engagepusher 802 a. Once the first inner slider 208 a is moved, theelectromagnet of the next slider 208 b is de-energized. This causes therespective torsion spring of slider 208 b to release. This sequence isrepeated for the remaining sliders.

In this embodiment, there are two stoppers 1102 a and 1102 b configuredto stop inner sliders 208 and outer sliders 206, respectively. Whenstopper 1102 b is activated, the arm of 704 a pushes against 1102 b.Once the cup 804 a turns, pusher 802 can pass through freely. Next, oncethe electromagnet of slider 208 b is turned on, slider 208 b stays inplace. This is repeated until all of the sliders come into a parkedposition. In some embodiments, when all of the gripper-assemblies 224are grouped and in their parked position (for instance, in the verticalposition), the electromagnets in the one or more sliders 206, 208 of thegripper-assemblies 224 can be de-energized.

FIGS. 14A-14C and 15A-15C show another exemplary retractable tractionsystem 104. In this embodiment, the retractable traction system 104includes two faceplates or discs 300, 301. Faceplate 300 is adjacent tothe wheel 102 and has a larger diameter then the faceplate 301furtherfrom the wheel 102. As shown in more detail in FIG. 14C, both faceplates300, 301 are engaged with each other via poles 1202 starting at thelarger faceplate 300 and extending into the path of the smallerfaceplate 301. In yet another embodiment, both faceplates 300, 301 maycontain poles 1201 and 1203. The combination of the poles 1202 and thefaceplates 300, 301 or poles 1201, 1203 and the faceplates 300, 301 areconfigured to hold in place strut 1424. Strut 1424 is located on thesmaller faceplate 301. As shown in FIGS. 14A and 14B, cleat 1422 may bepushed against the larger faceplate 300 in a disengaged position. Theretractable traction system 104 is activated when stoppers 1302 (shownin FIGS. 14A and 14C) are extracted from the smaller faceplate 301 viathe stopper holes 1301 on the smaller faceplate 301 and activate springs1408 that rotate the smaller faceplate 301 in relation to the largerfaceplate 300 which may be attached to the wheel 102. As the retractabletraction system 104 moves from the disengaged position to the engagedposition, the rotating top part of a cleat 1422 is moved above thesurface of the tire 106. Torsion springs 1405 continue to unwind untilthe cleat 1422 is pulled down and held on top of the tire 106 in theengaged position, as shown in FIGS. 15A and 15B. As shown in FIG. 15C,the retractable traction system 104 is deactivated when mechatronicscylinder 1401 pulls down shelf 1407 attached to the top of the spring1408 and allows stopper 1302 to be retrieved into the stopper hole 1301on smaller faceplate 301. At this time, torsions spring 1405 winds downthe cleat 1422 to the side of the tire 106 and causes the cleat 1422 tomove to the surface of larger faceplate 300, as shown in FIGS. 14A and14B in the disengaged position. The retractable traction system 104 maybe already integrated, as part of the wheel 102 and turn with the wheel102 or the retractable traction system 104 may be attachable to theexisting wheel 102.

The embodiments of the invention described above are intended to bemerely exemplary; numerous variations and modifications will be apparentto those skilled in the art. All such variations and modifications areintended to be within the scope of the present invention as defined inany appended claims.

What is claimed is:
 1. A system for retractably deploying enhancedtraction of a wheel, the wheel having a tread and an axis of rotation,the system comprising: a set of grippers, each gripper having a cleatand a radially disposed strut; a set of first poles, each first polecoupled to one of the struts, the first pole configured to supportmotion of its corresponding strut between a parked position and anengaged position, wherein, in the engaged position of such strut, thecorresponding cleat is axially disposed and engaged against the tread ofthe wheel and, in the parked position of such strut, the correspondingcleat is disengaged from the tread of the wheel; a first faceplateconfigured to rotate with the wheel, wherein, when such strut is in theengaged position, such strut is coupled to the first faceplate and moveswith the first faceplate and the wheel, and, when such strut is in theparked position, the strut causes the cleat to be in a correspondingdisengaged position, withdrawn in a radial direction from the tread; anda cleat deployment mechanism including: a second face plate rotatablycoupled to the first faceplate and configured for rotation between firstand second positions, and a set of second poles, each second polecoupled to one of the struts and to the second faceplate, and configuredso that rotation of the second faceplate between the first and secondpositions causes corresponding motion of each strut between the parkedand engaged positions respectively.
 2. A system according to claim 1,wherein the cleat is configured to rotate axially relative to the strutand is coupled to a torsion spring to bias the cleat in the disengagedposition.
 3. A system according to claim 1, wherein the second faceplateis reversibly latched in the first position by a set of stoppers.
 4. Asystem according to claim 3, further comprising a set of springs,coupled to the second faceplate, the set of springs being configured tobias the second faceplate against the set of stoppers when the stoppersare deployed, and to rotate the second faceplate to the second positionwhen the stoppers are retracted.
 5. A system according to claim 4,further comprising a set of actuators, coupled to the second faceplate,the set of actuators being configured, when activated, to rotate thesecond faceplate from the second position to the first position and inso doing to compress the set of springs coupled to the second faceplate.